Advertisements
Advertisements
प्रश्न
Find the sum of first 16 terms of the A.P. whose nth term is given by an = 5n – 3.
Advertisements
उत्तर
Given, nth term of A.P. is an = 5n – 3
∴ a1 = 5(1) – 3 = 2
And a2 = 5(2) – 3 = 7
∴ Common difference, d = 7 – 2 = 5
∴ Sum of n terms of A.P., Sn = `n/2[2a + (n - 1)d]`
∴ S16 = `16/2 [2(2) + (16 - 1)5]`
= 8(4 + 75)
= 8 × 79
= 632
संबंधित प्रश्न
Find the sum of all numbers from 50 to 350 which are divisible by 6. Hence find the 15th term of that A.P.
Find the first term and common difference for the A.P.
`1/4,3/4,5/4,7/4,...`
The sum of the first n terms of an A.P. is 4n2 + 2n. Find the nth term of this A.P.
Write the nth term of an A.P. the sum of whose n terms is Sn.
Q.11
Q.15
If the sum of the first four terms of an AP is 40 and that of the first 14 terms is 280. Find the sum of its first n terms.
How many terms of the A.P. 24, 21, 18, … must be taken so that the sum is 78? Explain the double answer.
In an A.P., the sum of its first n terms is 6n – n². Find is 25th term.
Which term of the Arithmetic Progression (A.P.) 15, 30, 45, 60...... is 300?
Hence find the sum of all the terms of the Arithmetic Progression (A.P.)
